UPDATE 1-MetroPCS reports higher Q1 customer additions

* Q1 net addition of 684,000 customers

* Q1 churn rises to 5 pct

April 7 (Reuters) - Low-cost mobile phone service provider MetroPCS Communications Inc (PCS.N) posted 51 percent growth in net customer additions for the first quarter, helped by growth in Northeast markets and core markets.

MetroPCS reported consolidated net additions of about 684,000 subscribers in the quarter.

"Building on the momentum in subscriber growth we reported during the fourth quarter of 2008 and with our concurrent launches of service in the New York City and Boston metropolitan areas, we are off to a very strong start for 2009," Chief Executive Roger Linquist said in a statement.

However, churn -- a measure of customer attrition -- for the first quarter rose to 5 percent, compared with 4 percent in the year-ago quarter. (Reporting by Supantha Mukherjee in Bangalore; Editing by Himani Sarkar)